This invention relates in general to boomerang-type flight toys and, more specifically to a multi-bladed boomerang toy having improved flight and return characteristics which is safe for use indoors.
The earliest boomerangs had a very broad V-shape, with two flat blades extending from a centerpoint. Those boomerangs were used primarily as an aboriginal hunting weapon which would fly in a flat circle while rapidly spinning, returning to the location of the thrower. The return characteristics were useful in retrieving the boomerang if the thrower missed the target. These boomerangs were large and heavy, with sharp edges, made from strong wood. The returning boomerang would be allowed to strike the ground, since attempting to catch it would be very dangerous.
A great number of boomerang toys have been developed over the years which attempt to retain the return flight capability while improving performance and allowing the boomerang to be safely caught. Many of these have multiple blades extending from a central hub, such as those described by O'Brien in U.S. Pat. No. 4,452,461, by Hunt in U.S. Pat. No. 4,772,030 and by Robson in U.S Pat. No. 4,421,320.
A variety of other flight devices, such as the popular "Frisbee" flying disk have also been developed. These devices do not act in the manner of a boomerang which is thrown in a generally circular path parallel to the ground over large distances and returns to the thrower. Instead, the flying disk type devices when simply thrown upwardly at an angle, generally into the wind, "slide" back down to the thrower.
Boomerang flight apparently results from a combination of gliding, gyroscopic action from the rotation and lift from the blades. A boomerang must be accurately constructed so that these combined effects produce the desired flight characteristics. Many hand made boomerangs fail to fly properly despite being apparent close copies of fully operative boomerangs. Most prior boomerangs are difficult or impossible to adjust and require considerable skill for proper flight. Adjustable boomerangs, such as is described by Liston in U.S. Pat. No. 3,565,434, have been developed to permit the used to modify and fine tune the flight properties. Unfortunately, these boomerangs are easily knocked out of adjustment by contact with the ground, hazards such as trees or even during catching the boomerang. The need for extensive readjustment between flights is clearly undesirable.
Traditional boomerangs are made from wood or, today, from rigid plastic materials. These are difficult to catch safely and are particularly dangerous to children and bystanders. Attempts have been made to pad the boomerang with soft material or use soft leading edges as described by Adler in U.S. Pat. Nos. 4,222,573 and 4,479,655. While initially safer and more easily used, these boomerangs suffer from impaired flight characteristics where the covering becomes deformed and are dangerous where the covering is damaged, exposing the rigid inner structure.
The size, weight and rigidity of prior boomerangs generally prevented their use by small children indoors, because of the danger to home furnishings and to the users.
Thus, there is a continuing need for improvements in boomerang toys to overcome the problems noted above, to improve flight and return characteristics and to improve safety and permit safe use by children and indoors.